I believe the example of an environmental variation in the above question is, A. Marge dyes her hair blue. Variation represents any difference between cells, individual organisms, or groups of organisms of any species caused by either genetic differences or by the effect of environmental factors. Environmental variation is the ability of an organism to alter its phenotype depending on environmental conditions.
"<span>The genes for melanin pigmentation remain turned on and prepare more melanin than usual to protect the skin from photo-damage when it is exposed to sunlight for long time" is the actual reason. </span>
Answer:
It can reduce carbon in the atmosphere.
Homeostasis is maintained through feedback because when one certain parameter of your body goes out of the homeostatic bounds, feedback mechanisms will message this back towards the regulatory mechanisms which are responsible for homeostasis maintenance in the first place. Another thing, other than death, which can happen would be a higher bodily temperature for example.